1. Field of the Invention
This invention relates to apparatus for adjusting a diaphragm in a flash mode to a size that corresponds to scene brightness and to focus of the camera with distance to the photographic object.
2. Description of the Prior Art
Commonly assigned U.S. Pat. No. 3,714,871 issued to Richard J. Bresson discloses camera diaphragm apparatus in which the relative position of first and second diaphragm blades are controlled in relation to scene brightness by a differentially-controlled motor. The relative position of the diaphragm blades is continually varied as scene brightness varies to effect corresponding changes in the size of an exposure aperture. When scene brightness decreases to a predetermined level, the apparatus adjusts the blades to set the exposure aperture at its maximum size; a tripod may be required for using an extended exposure time. On the other hand, the operator may choose to use auxiliary light e.g., a flash unit.
The apparatus of the Bresson patent responds to the flash unit being mounted to the camera by actuating a focus controlled linkage that acts on the diaphragm blades to adjust the exposure apertures during focus adjustment. The blades are made of thin metal and any torque acting directly on the blades may possibly cause the blades to buckle. By transfering any linkage torque directly to the motor, the possibility of buckling is eliminated.